1. Field of the Invention
The present invention relates to movable body apparatus, exposure apparatus and optical system units, and more particularly to a movable body apparatus that is equipped with a movable body which moves holding an object, an exposure apparatus that irradiates an energy beam on the object via an optical system and forms a predetermined pattern on the object and an optical system unit suitable for use in the exposure apparatus, and a device manufacturing method using the exposure apparatus.
2. Description of the Background Art
Conventionally, in a lithography process to produce a semiconductor device, a liquid crystal display or the like, a projection exposure apparatus by the step-and-repeat method (the so-called stepper) or a projection exposure apparatus by the step-and-scan method (the so-called scanner) is mainly used that transfers a pattern formed on a mask or a reticle (hereinafter generally referred to as a “reticle”) onto a substrate (hereinafter also appropriately referred to as a “wafer”) such as a wafer or a glass plate on which a resist or the like is coated via a projection optical system.
In these exposure apparatus, further improvement of resolution of the projection optical system is becoming required due to higher integration and finer patterns in a semiconductor device. Therefore, the wavelength of the exposure light is becoming shorter year by year, and recently, development of an EUV exposure apparatus (EUVL) which uses an SOR (Synchrotron Orbital Radiation) ring, a laser plasma light source or the like that generates an extreme ultraviolet light (EUV (Extreme Ultraviolet) light) of 100 nm or less as the exposure light source is underway.
In the EUV exposure apparatus, because there are no optical materials at present having a suitable transmittance to EUV light, an optical system of total reflection consisting of only reflection type optical members (catoptric elements) is employed as the projection optical system and the illumination optical system, and a reflection type reticle is also used as the reticle. Further, because the EUV light is absorbed by most materials, the optical path space of the EUV light needs to be set in a predetermined high vacuum state, and the EUV exposure apparatus main section is usually installed in a vacuum chamber (refer to, for example, Kokai (Japanese Patent Unexamined Application) No. 2005-276932 bulletin).
However, when the whole exposure apparatus is placed in a vacuum chamber, the size of the whole apparatus will increase and it will also take a lot of time to set the inside of the vacuum chamber to a vacuum environment. Further, because access to the apparatus in the vacuum chamber from the outside is relatively difficult, maintenance operation will take a lot of time and effort. Further, there are cases when the vacuum chamber is deformed by a difference in pressure inside and outside the vacuum chamber, and by the deformation, positional relation of each section of the exposure apparatus may fluctuate, which may cause a decrease in the exposure precision.
Further, also in the EUV exposure apparatus, in order to improve the exposure accuracy, it is desirable to measure the surface position information of the wafer and the reticle and perform exposure operation taking into consideration the measurement results, as in the optical exposure apparatus.